Keep your screen unlocked... – Sleep Time zZz — Sleep Cycle Alarm Clock with Sleep Aid (Free) Review

The app gets the job done, but you have to reset your setting. I agree with the earlier post that if you lock your phone, move it, or basically do anything accidentally after setting the alarm, you're screwed. This has happened to me a couple of time to the point where I think I'm going to try a new app. I get the intended purpose, and that's great, but it's super annoying.
Review by Roons83 on Sleep Time zZz — Sleep Cycle Alarm Clock with Sleep Aid (Free).